System of making and recording profile measurements



March 8, 1955 B. J. sMYTH 2,703,456

SYSTEM OF' MAKING AND RECORDING PROFILE MEASUREMENTS Filed April 13.194e 7 sheets-sheet 1 H/ m 3X W Wap/V57 March 8, 1955 B 1 SMYTH2,703,456

SYSTEM OF MAKING AND RECORDING PROFILE MEASUREMENTS Filed April l5,V1948 7 Sheets-Sheet 2 MNH B. J. SMYTH March 8, 1955 SYSTEM OF MAKINGAND RECORDING PROFILE MEASUREMENTS Filed April 13, 1948 7 Sheets-Sheet 3f IIYI.

March 8, 1955 B, J SMYTH 2,703,456

SYSTEM OF MAKING AND RECORDING PROFILE MEASUREMENTS Filed April 15, 19487 SheeIS-Sheet 4 H770 ENEY B. J. sMYTH 2,703,456

SYSTEM 0E MAKING AND RECORDING PROFILE NEAsUREMENTs March 8, 1955 7Sheets-Sheet 5 Filed April l5. 1948 Hrw elvfy March 8, 1955 E, SMYTH2,703,456 i SYSTEM OF' MAKING AND RECORDING PROFILE IVEASUREIVIENTSvFiled April 13, 1948 7 SheetS-She' 6 March 8, 1955 B- J, SMYTH 2,703,456

SYSTEM OF MAKING AND RECORDING PROFILE MEASUREMENTS Filed April 13, 19487 Sheets-Sheet '7 40 ml/ m I ER United States Patent y'SYSTEM 0F MAKINGAND RECORDING PROFILE MEASUREMENTS Bertram J. Smyth, deceased, klate ofOberlin, Ohio, vby Ruth B. Smyth, administratrix, Oberlin, Ohio,assignor, by mesne assignments, to Measuring Machines Inc., Cleveland,Ohio, a corporation of Ohio Application April 13, 1948, vSerial No.20,5822

13 Claims. (Cl. 33--174) (Granted under rlitle 35, U. S. vCode (1952),sec. 266) This invention relates to a system of making and recordingprofile measurements and includes the method of operation, the peculiarrecord produced thereby, and an eicient apparatus for carrying out themethod. The measurements are made and recorded by the employ ment of afeeler to engage the surface of the article to be measured and a mirroroperated in conformity to the movements of the feeler to direct a beamof light onto a photographic film. Such method and apparatus 'areparticularly well adapted to make a magnified record ,of profiles ofirregularly shaped objects s o that very minute variations on thesurface may be readily observed on the record chart produced. n

One of the objects of the invention is to produce a visi' ble scalephotographically on la film during the succession of operations ofrecording the prole, so that there will be certainty of registrationbetween the `scale and the profile indication, and the 'produced sheetwhich be independent of stretching or shrinking of the sensitized aper.y

Another object is to 'produce a simultaneous measurement from opposite"sides of the object `to give the cross sectional dimensions thereof vinsuccessively inspected reions. g Still another 'object is to providereadily operable means for accurately positioning the article yto bemeasured, 'so that vmovement 'thereof relative -to the feelers n iay bealong a line parallel with a chord of a curved article, so that therecorded measurement may be accurate from Ta datum line on thephotographic'sheet.

In the system of this invention, means are provided 'for advancing thefilm 'and simultaneously moving 'the article to 'be measured, andlautomatically controlled switches are provided for sources ofillumination so that-scale-may be formed on the film 'by marks ofreadily recognizable character and the measurement may be superimposedin the scale spaces by marks Vof a diferentfcharacter: Prefe'rably thephotographic formation of -the scale is made while the film is moving,`thus producing elongated marks, while the photographing --of thearticle Vmeasurement is made when the film is stationary, -so as toproduce dots or similarly small indications which in association w-iththe -scale produce a final record chart giving -the exact measurementsof the region measured.

The invention includes also an apparatusfor-effectively1 carrying outthe above objects as illustrated in the drawings hereof and hereinaftermore fully described. T his apparatus operates on the general -principleof yturning a mirror on an axis by the shifting `of -a feeler engagingthe article to be measured, such mirror `serving to dir ect illuminationto a photographic film to make chemical changes therein which when thefilm is developed will produce marks Ion the film. Another source ofillumination, acting through a grid, photographical'ly produces adimensional scale on the film, alternately with the photographing of themeasurement of the article, so that the marks on the nlm, respectivelyof the scale and the measurements, are properly correlated.

The apparatus in its `preferred form tests opposite points on thearticle and produces on the film indications which will show inmagnified form the cross sectional distance across the article in theyregion measured.

All of the above operations and features will be clear from thelfollowing description of preferred embodiments illustrated in thedrawings. l 7

In the drawings, Fig. l is a plan partly 1n section of one iceembodiment of the apparatus of this invention; Fig. 2 is a sectionalside `elevation of the same; Fig. 3 is an enlarged view of the mirroroperating mechanism of Fig. l; Fig. 4 is a vertical section of suchmechanism in offset -planes, as indicated by then-line 4-4 on Fig. 3;Fig. 5 is a transverse section in offset planes indicated by the line5-5 on Fig. 3; Fig. 6 is a detail of the mirror turning mechanism, in aplane indicated by line 6-6 on Fig. 3 Vbut on a larger scale; jFig. 7 isa horizontal section on a line 7-7 in Fig. 6; Fig. 8 is a diagramillustrating the operation of the article movement, the film feed, andthe actuation of various switches all controlled by a master motor; Fig.9 is an enlarged horizontal section through the scale forming grid shownin Figs. l and 2; Fig. ll0 is `a face View of a portion of the recordchart produced by the apparatus; Fig. ll is a plan of modification ofthe article measuring `and mirror portion of the apparatus; Fig. l2 isan enlarged vertical section of such modification in a plane indicatedby the line 12-12 on Fig. 11; Fig. 13 is a horizontal section throughsuch modification in offset planes indicated by the lines 13-13 in Fig.12; Fig. 14 is a vertical section through this modification, asindicated by the line 14--14 on Fig. l2; Fig, l5 is a View in verticalsection Iillustrating means for enabling the photographic formation of adatum line on the chart.

Referring rfirst to Figs. yl and 2, 10 indicatesa suitable base on whicha vertically adjustable block 11 carrying a slide 12 adjustable fromvfront to back of the machine. Any suitable means may be employed formanually adjusting the supporting block -and transverse slide. Fig. 2indicates, for instance, la screw 13 rotatably mounted in the block 11and threaded in the slide and adapted to be operated by a crank 14 (Fig.l). Similar means (not shown) may be used for raising and lowering theblock.

Mounted on lthe ytransversely movable slide 12 is a longitudinally`movable slide 1S `and mounted on this slide is a yturntable V1'6equipped with suitable clamp or holding device 17 for holding thearticle to ybe measured. Such article inthese figures is indicated as animpeller blade A. The vertical adjustment of the supporting block, andthe horizontal adjustment of the lateral slide, and the rotativeadjustment yof the turntable are all performed manually and the partsbecome locked in position when set. The longitudinal slide 15, von theother hand, is moved during the -operationlo'f the apparatus. To providefor 'such movement, Fig. 2 shows a screw 20rjournaled in thetransverseslide 12 and threaded in an ear 21 depending from thelongitudinal slide. 25 indicates an operating motor for the longitudinalslide, the armature 'shaft being indicated as connected by spiralgearing y25 t'o the lscrew 20. The time of operation of this motor withreference to -`the rest of the apparatus will be hereinafter described.

By adjust-ing the table '16 about its axis one is able to position thearticle to be`tested so that its movement by the longitudinal slide willbe .parallel with va tangent to 'one 'side of the article. The articleto be measured, as for instance, a turbine blade, is shown at A. Whenthis hasbeen 'clampedto the table, -the table is -adjusted about itsaxis by a pair of Vmicrometer screws 30 and 31 which abut upstandingpins 32'and 33 rigid with the table. The 'adjustment of these screwsaccurately positions the table andv holds it when set.

The mechanism which 'tui-ns the mirrors in accordance with the rprofilesof the varticle is shown `in one form in Figs. 1 to 6 and in another'form in Figs. l1 to 14. Each of these embodiments has a pair oflongitudinally extending arms 40, in Fig. l,y or 80, in Fig. ll,suitably pivoted b y individual pivots 4,1, in Fig. l, or by a common@pivot 81 for both arms in Fig. 1l. ln either case each -feelerarmcarries Ia feeler point42 or 82 7to engage opposite sides of ythe'article and each arm carries a rack 253, )in Fig. l, or'83 in Fig. ll,to engage a pinion for turning a mirror as 45, in Fig. l, or 85, in Fig.11 The specific vconstructions illustrated in :these two embodimentswill 'be hereinafter described in detail.

Stlin varousfigures designates -a source of light, the rays -52 of whichpassing through a focusingple'ns 5-1, act `on t'he mirrors '45"or, 8S todirect a beam 53 'through Va horizontal `s`lit in 'the housingcontaining a Vphotog'raphic film, to cause indications thereoncorresponding to 'the 2,703,456 f Y a position of the feeler engagingthe article, though greatly magnified as to actual distance.

60 in Figs. 1 and 2 indicates a roll of lm B, as sensitized paper. Suchpaper is caused to travel in a plane from this roll with the sensitizedside toward the measuring apparatus. To progress the film a pair ofrolls 61 and 62 are provided, the former of which is rotated by suitablemechanism actuated by a motor 70. This motor may operate continuouslyand be connected periodically, by suitable intermediate mechanism, ashereinafter described, to operate the film advancing roll 61.

A suitable housing indicated at 64 encloses the film and the drivingrollers therefor. The lamp 50 is outside of this housing and itsreflected beams enters through a narrow horizontally extending slit 65to effect the photographic impression on the film behind the slit.

66 designates a second source of light adapted to direct a beam 54through the same slit 65. Interposed between this light and the slit isa grid or a comb 67 stationarily carried, as by brackets 68 from thehousing 64, this comb extending transversely of the direction of movement of the film. The comb is preferably curved concentrically about thesource of light 66.

In the operation of the apparatus, after the object has been clamped andaccurately located in position, the film driving connection is startedin movement to progress the film, and the lamp 66 is lighted with theresult that its rays passing through the comb and the slit 65 make atransverse row of photographic indications on the film, and as the filmis progressing a short distance during this illumination theseindications are in the form of short lines or dashes. As theillumination is intermittent, there are produced on the film, at eachcycle of operation, a series of these lines in a transversely extendingrow, adjacent rows being separated by a transverse blank space.

More specifically stated, if the film is progressing vertically, asindicated in Fig. 2, the short lines extend vertically and are spacedapart horizontally by the action of the comb and vertically by blankdistances resulting from extinguishment of the illumination betweensuccessive cycles. Each row of vertical dashes or pickets thus formedextends horizontally across the film. The result is the formation on thefilm, after successive operations (after the film has been developed) ofa succession of vertically spaced horizontal rows of visible marks, themarks in each row being vertical pickets or dashes and such pickets ordashes being in alignment in vertical rows.

The above result is indicated in Fig. 9, wherein 1, 2, 3, etc. indicatethe vertical rows of individual dashes made by the light while the paperis moving, the corresponding dashes in successive vertical rows aligningand forming horizontal rows, indicated by a, b, c, etc.

Now with this apparatus, one can form, on the same film and during thesame operation with the production of the scale, a series of dotscorresponding to the position indicated by the two pointers 42. Thesedots are made by the light from the source 50 reflected by the mirrors45 directly through the slit 65 while the film is stationary. Fig. 9shows a course X of such dots indicating one face of the object measuredand a course Y indicating the opposite face.

In other words, at a proper time while the film is stationary the lightS is illuminated and its beam is reccted by the two mirrors 45 in acourse out of range of the comb 67, but passing through the same slit 65in widely different positions, as indicated by the two reection lines 55in Fig. l. As this photographic indication is made at the time the filmis stationary between two dash-forming advancements thereof, thereresults a series of dots located in the spaces between successive rowsof dashes, one series of these dots (X, for example) indicating theconditions on one side of the object A, the other series Y, indicatingconditions on the opposite side.

After the sheet has been developed these dots may be readily connectedmanually by a line to give a greatly magnified curve corresponding tothe profile of the article. The distance between any two correspondingdots (measured parallel with the adjacent row of dashes) corresponds tothe cross sectional distance across the article at the correspondinglocation. As the carriage is moved simultaneously with the movement ofthe paper, each succeeding dot photographed onto the paper when it isstationary comes on a different place on the photographic sheet andrepresents the new location on the article.

As the length of the dashes depends upon the length of time the lm isadvancing, and as during this time the carriage is moving a definitedistance, it follows that each successive horizontal row of dashescorresponds in the apparatus shown to a different region of the feelerengagement with the article, and as the film is advanced at a fasterrate of speed than the article, relatively small movements of thearticle may be readily visible on the lm. Furthermore, as themagnification is very great a very small change in the shifting of themeasuring points results in a much greater horizontal positioning of thedots between the rows of dashes. Accordingly, though the difference insuccessive measurements of the article may be only a few thousandths ofan inch, such difference is readily visible on the chart.

Likewise, by counting the number of dashes between corresponding pointmarks on the chart, for opposite sides of the article, one may readilyobtain the actual distance across an article at that region. Forexample, if the distance from the center of one dash to the center ofthe next in a horizontal row is .10 of an inch, then if there arefifteen dashes with their spaces between the two dots of a pair we knowthe actual cross sectional distance is 1.50 inches. The horizontaldistance between the dashes of a given row is determined by the spacingof the comb and is fixed at any convenient amount.

A close inspection of Fig. 10 will show that in each vertical course ofdashes every fourth dash is made heavier. This is for the purpose ofenabling the ready counting of the number of dashes. It is effected byrelatively intensifying the light from the source 66 for every fourthoperation, such intensification being effected by cutting out resistancein the lamp circuit from its nor- Amal condition for the otherhorizontal rows of dashes.

It will likewise be seen in Fig. l0 that every tenth vertical row ofdashes is emphasized by being made heavier. This aids in counting thedistance transversely of the chart. It is effected by making every tenthopening in the grid 67 wider than the normal openings, as indicated foreX- ample by the special openings 68. The rays of light through thenormal spacing in Fig. 10 producing the normal width of dash, isindicated by S, Fig. 10, whereas the specially wide formation to givethe heavier dash, is indicated by the more divergent rays T in thisfigure.

It is desirable to print on the chart, Fig. 10, a datum line Z spaced aproper distance from the dashes so that measurement on the chart may bemade if desired from such datum line. To effect the printing of thisline there is provided in the film housing 64 a special slit 180 locatedat the proper distance from the slit 65 through which the normalexposures are made. This slit is normally closed by a gate in the formof a roller 181 carried by a pair of pivoted end arms 182 which aredrawn in the closing direction by a spring 183. Ordinarily, therefore,the slit 180 is idle. When, however, it is desired to print on the filma straight horizontal datum line this is done by merely swinging theframe 182 to carry the gate 181 from the position shown in full lines inFig. 15 to the dotted position 181a where it operates to close theopening 65. In this position ordinary daylight admitted through theopening 180 will act on the film to produce the datum line Z.

It is preferable to correlate the movement of the roller 181 with thefeeding of the film so that a fresh portion of the film may be drawnopposite the opening 180 whenever the latter is exposed. This may bereadily effected, as indicated in Fig. l5, by providing a manuallyoperable arm 185 pivoted coaxially with the film feeding ratchet 90 andcarrying a pawl 186 adapted to engage such ratchet. This hand lever 185is connected by a link 187 to the gate carrying frame 182. Accordingly,when the hand lever 185 is shoved downwardly from its full line positionin Fig. l5, to its dotted line position in that figure, it operates toadvance the film and simultaneously shifts the normally closed gate 181to its upper position to open the printing slot 180. This enablesdaylight passing through such slot to print the datum line on the sheetphotographically.

I have referred to illumination from the source 66 passing through thecomb 67 and entering this same siit 65 in the film housing, The comb, asshown in Fig. 2, is carried by suitable brackets 69 extending from thefilm housing. The comb is preferably arcuate in form, as shown in Figs.1 and 1l. To make the illuminations of the planular film equidistant,though coming through `arcuately positioned slits .of the comb, the comb'spaces l(with the exception of certain extra 'wide 'spaces 'here-`inafter described) are gradually reduced -in size from the centralregion in'each direction, so that rays of light, as indicated at S inseveral positions in Fig. 9 eilect the same spacing on the photographicfilm, `as if the comb were a straight member with slots through it atdifferentially arranged angles in the direction of the beam to passthrough the slot. lt'has been found simpler, however, 'to zprovide acomb concentric about the lamp and arrange the slots in the radialdirection though of varying Width, as stated. The master motor 70 ispositioned a't any suitable point in "the `apparatus and operates tocontrol the advancement ofthe flm'and also to initiate the actuation ofthe motor 25 which moves the slide 15.

The actuation'of thefilm may be readily effected by a ratchet wheel 90,Fig. 8, on a shaft 91 which carries one of the wheels :61 which incoaction with the opposite wheel 62 engagesthe film B. The ratchet wheelis shown asactuated by alpawl 92 on a sliding link 93 which carries aconcentric strap surrounding an eccentric 95 on the armature shaft ofthe motor 70. With this eccentric connection and the motor 70continuously running, then the downstroke of the Avertical link 93 isidle for a half rotation of the motor, but during the other halfoperates t'o lturn the ratchet 91-one tooth to turn the wheel 61 to feedthe film. The actual timing will b'e explained running and periodicallyoperating the film feed as well as operating a cam which successivelycauses the electric connections to 'effect different operations. Theorder of the operations effected by the master motor 70 is as follows:

1st. Closes the starting circuit to thefcarriage motor 25. 2nd.Energizes the film drive. 3rd. Closes `the circuit to the scale lamp 66.

4th. Opens the starting switch for the carriage motor.

5th.-Opens scale lamp circuit. 6th. Closes the circuit to the plotting1arnp'50. 7th. Opens the circuit to the plotting lamp.

The film feed on every fourth stroke cuts out a resistance R in `thecircuitof the scale lamp to make a heavier impression.

The operations of starting the carriage motor and starting the paper maytake place simultaneously, and likewise the stopping of the carriagemotor and the opening of the scale lamp circuits. The scale lamp is onfor a sufficient length of time to produce the desired dash on 4thesheet, depending on ythe speed of the motor advancing the film. Theplotting light operating while the film and object are ystationary needbe on lonly long enough to make a proper photographic exposure.

Fig. 8 indicates by way of example a wiring diagram indicating Yelectricyconnections to the two motors 70 and 25 and the two lamps 50 and 66 toeffect the operations heretofore stated.

In the wiring diagram, Fig. 8, the current is presumed to come from oneof the two lines C, past a main controlling switch D to -and rfrom thelines E and F. From the lines E and F, lines G and H lead to the mastermo- `tor 70. Likewise from these lines E 'and F, lines I and I leadthrough the plotting light 50 and its controlling switch 99. A lineK isshown leading from the line I through thescale light switch 98 to thescale light 66 and then normally through a resistance R 4to the line Land thence to the vline F. From the line F, a line M leads through areversing switch N to the motor 25 and thence via the line P through acommon contact Q1 of a makebefore-break switch Q, thence through one Q2of this switch through the line U, to the initiator switch 97 and fromthis switch through the lines K to the power line E. IShortly a'fter themotor 25 is energized the cam 170 operates the switch Q to establish acircuit from the motor 25 through the line P, the common contact Q1 andthe other side Q3 vof the sWitch'Q, a line Q4 directly to the powerKline E, and immediately thereafter to break the 6 'circuit between themotor 25 which was established by closing of the initiatorswitch 97.

The advancement of the carriage is ordinarily for a Very short distance,as it may be desired to take measurements as often, for example,as every.025 inch. Accordingly, the stopping of motor 25 is controlled by theopening of the switchQ by the cam A170, which is rotated by the workadvancing screw 20. This cam opens the direct'circuit between the motor25 and the power line E, vand reestablishes the circuit between suchmotor and the power line through the initiator switch 97 which wasopened by the main control cam 95 long prior to the reestablishment ofthe circuit through it to the motor 25. The switch Q, therefore, acts asa limit switch and controls the distance travelled by the carriageduring each cycle of operation.

Lines V and W lead from` opposite sides of the resistance R to a specialswitch 164 which is adapted to be closed by a cam 165. The cam hasone-fourth as many humps as there are teeth on the ratchet 90, so thatevery fourth stroke of the feeding ratchet will be accompanied by ashort circuiting of the resistance in the scale light circuit, thusgiving more intensive illumination and producing the heavy marks ofdashes throughout every fourth horizontal row, as shown in Fig. l0.

The rst operation of the cam 95 is to close the switch 97 and passcurrent to the motor 25 Via the lines E, I, K and U to the closed switchQ to the line P and through the set reversing switch N to the motor andback via the line M to the line F. This starts the motor 25 rotating,and rotates the feed `screw 20 which advances the carriage and hence thearticle to be measured.

During the advancement of the work, under the control of the switch 97,the cam 95 operates to close the switch 98 energizing the scale light 66either through the resistance yR or through its kby-pass according tothe position of the cam 165. While the scale light is on, the pawlmechanism driven by the motor 70 operates the ratchet to advance the lm,such advancement continuing after the cam opens the switch 98. Thisresults in producing one row of dashes horizontally across the chart andproducing a horizontal blank space immediately following the row.

The next operation of the cam 95 takes place after the cam 170 hasoperated to open the limit switch to the motor 25 and during the idlestroke of the pawl 92. The result is both the article being measured andthe film are stationary at the time the cam acts on the switch 99 toclose the circuit through the plotting light 50. This results in thedirection of beams of light from the two mirrors 45 through the slit 65to produce two dots von the film corresponding to positions of theneedle points 42 on opposite sides of the article being measured.

It will be seen that with this mechanism there is produced not only ascale chart but during the same operation two series of dots, as'theseries X on Fig. l0 indieating one surface of the article beingmeasured, and the serles Y indicating the opposite surface, and thenumber of dashes in any horizontal row between the two lines made bythese two courses of dots indicates the exact cross sectional dimensionof the article in the region being measured. Successive measurementsbeing taken at equally spaced positions on the article, two lines, whichmay be subsequently drawn on the chart, connecting the two courses ofdots accurately portray in greatly magnied form not only the surfaceconditions of the article by the cross sectional dimensional at allmeasured regions thereof.

Reverting now to the first embodiment of the mirror actuating mechanismshown in detail in Figs. 3 to 7 inclusive, the two arms 40 are shown aspivoted by ball bearings 100 on two vertical studs 101 carried by theframe 10 of the apparatus. Each arm 40 is preferably bifurcated toprovide spaced ears 102 and 103, Fig. 4, carrying the respective ballbearings about the supporting stud. The racks-43 in this embodimentcomprise straight bars 105 adjustably secured at 106 to blocks 107 oneach of the arms 40. Vertical teeth 108 on each rack 43 mesh withpinions 110 which connect with the mirrors 45.

Als shown, the pinions i110 are rigidly mounted on a sleeve `which in'turn is rigidly secured to a ventioally extending shaft 1112. The lowerends of the shafts tl1l2 are journaled in jeweled bearings 1115 .carriedIby upstanding brackets y1|1'6 supported by thevbase 10, Iand |the upper'ends of'thesfe shafts are journalled in similar jeweled bearings 1t14carried by plates L1f17 carried by the brackets 11'6 rigidly mounted orformed integral the base d0. Sleeves .120 are xedly mounted on theshafts 1'112, and formed integral with the sleeves 120 are discs 1211.Se-

cured to diametrically opposite regions of each of these v discs is anupstanding bifurcated plate 122 on which the respective mirrors 45 aremounted.

A screw i109 having a knurled head is threaded in the inner end of eachrack, and .these two screws by abutting each other form proper stopslimiting the inward movement of .the arms when the feeler points 42 arejust about to touch, as shown in Fig. y3.

Means `are provided .to give the .arms a tendency to move toward eachother to the limit. The means shown in Figs 3 to 5 comprise a pair ofpermanent magnets 125 secured to short arms 126 projecting inwardly fromthe respective arms 40. These magnets overlap each other with oppositepoles adjacent so that they tend to draw the arms 4t) together.

To prevent any backlash in `the gearing from the rack bars vt3 to thepinions 1.10, a pair of springs 128 are provided which are secured atone end 129 Ato the respective arm, the spring being constrainedlaterally to act on the rotating disc 121 which carries the pinionmeshing with the gear. By .this means the pinion teeth are alwaysmaintained tight against the rack teeth in the direction toward thespace between the arms and any looseness in the gearing is avoided.

It will be understood from ythe above specific description that a veryaccurate mechanism has been provided for converting the movement of theffeeler point 42 into a movement of the mirror 45.

In place of the specic mechanism just described, one may employ `themechanism of Figs. l1 .to `14. in that case the two 'arms 80 are shownas pivoted tat 81 on a single pivot carried by a post 130 rising fromlthe base. Each arm 80 carries an @arcuate rack 83 which `engages apinion `132 rigidly connected to the mirror carrier.

The mirror carrier in this instance is an olfset bracket 1 3`5 having`an upwardly extending Wing i136 on which the mirror is mounted. Themirror may be slightly tipped one way or the other by reason tof taspring portion 137 of this bracket adjusted by Ia screw 1738, Fig. 14.The pinion with its bracket is rigid on a vertical shaft 1140 which ismounted in jeweled bearings at the lower end in a stud M1 mounted in asuitable frame support 142, while at the upper end a jewel bearing iscarried by a cross bar A145 secured to upright portions of the framebracket |142.

Surrounding each pinion shaft 140 is `a hair spring (147, connected atone end .to the shaft 'and at the other to a stud 148 `depending lfrom'the frame bar 145. These hair springs take up any backlash in thegearing between the racks `1321 and the pinion-s 132, and tend to swingthe arms -80 to retain the feeler points -82 in contact with the workpiece A.

The mechanism just described, it will be seen, provides for accuratelyturning the ymirrors in correspondence with the movement of the feelerpoints, and this mechanism may be employed in place of that shown inFigs. 3 to 6, if desired. In either case the operation is to reflect thebeam of light from the source of illumination 50 through the slit 65 inthe .iilm housing.

The invention described herein may be manufactured and used by or forthe Government of the United States of Amer-ica lfor governmentalpurposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. An apparatus for making `a photographic chart indicating proti'le`measurement of fan article, comprising a housing adapted to contain asensitized film, a feeler adapted to engage the article to be measured,a mirror, mechanism operated by the feeler for swinging it in accordancewith rthe movement of the feeler, a source of light adapted to bereflected by the mirror through a slit in the housing onto the frlm,means for `directing separated rays of light onto the film to produce ascale, means for alternately interrupting `the light reiiected by themirror and the Ilight from said separated rays, and means forprogressing the lm while the scale-producing light is effective andmeans for holding the iilm `stationary while lthe light reilected by themirror is effective.

2.. A contour recorder comprising i-n combinati-on, a specimensupporting carriage slrdably mounted, a pivoted ltracer arm having astylus adapted to |follow the surface 8 of a specimen carried by saidcarriage, a pivoted mirror adapted to deflect according yto movement ofsaid arm, a sourceof light `directed upon said mirror for reflecting abeam of ysuch light, :a light-sensitive lm in the path of the reflectedbeam with means for movingsard -rn accordance with movement of saidsupportrng carriage, a separate light source, a stationary scale-fornnnggrid interposed between said separate light source and said film forcasting shadows on .the film at points representing predetermined scaledivisions, and switch means for energizing said light sourcesalternately las the carnage 1s moved.

3. In a measuring apparatus, the combination of a movable slide, meansfor holding thereon an article to'be measured, a pair .of pivoted yarmshaving feelers eng-aging respectively :opposite faces of the article, apair of mirrors pivota-lly mounted and geared with the arms, whereby themirrors are turned in accordance with the movement of the feelers, ahousing adapted to contain a sensitized film, a source of illuminationproviding rays of light adapted to be idire'cted by the mirrors throughthe housing onto the film, a second source of illumination, a gridbetween said second source and :the hlm adapted 4to produce spaced markson the hlm, `a master motor, a switch mechanism controlled therebyadapted in successive order to initiate the movement of theslide-advancing motor to illuminate the scale light, to advance Ithe nlmwhile the scale light is illuminated, thereafter to extinguish the scalelight and thereafter to turn on the light reflected by the mirrors |ontovacant spaces on the film.

4. A continuous system for making and recording prole measurements,comprising mounting an object to be measured for movement in a straightline, continuously contacting the object to be measured with a follower,intermittently moving a light sensitive surface transversely past anopening in a housing enclosing the light sensitive surface, periodicallyexposing the light sensitive surface to a source of light transmittedthrough a shield while the light sensitive surface is moving to imprinta scale upon the light sensitive surface, alternately exposing the lightsensitive surface to a second light source while the light sensitivesurface is stationary and directing the light from said second source tothe surface along a path varied in response to variations in theposition of the follower, whereby a record of successive profilemeasurements and the scale by which they are to be measured areimprinted simultaneously in a single continuous operation.

5. A continuous system of making `and recording profile measurements,comprising mounting an object to be measured for movement in a straightline and in a direction normal to a planar light sensitive surface,continuously contacting the object to be measured with a follower,intermittently moving the light sensitive surface transversely withinthe plane in which it lies, periodically exposing `the light sensitivesurface to a source of light transmitted through a shield while thelight sensitive surface is moving Ito imprint 'a sca-le upon the lightsensitive surface, valternately exposing the light sensitive surface toa second light source while the light sensitive surface is stationaryand directing .the light from said second source to the surface along apath varied in response to variations in the position of .the follower,whereby a record of successive prole measurements and the scale by whichthey are to be measured are imprinted simultaneously in a singlecontinuous op eration.

6. A continu-ous system yfor making and recording protile measurements,comprising mounting an object to be measured for movement in a straightline and in a direction normal to a planar light sensitive surface,corrtinuously contacting the object to be measured with a follower,intermittently moving fthe light surface transversely within the planein which it lies a-rrd simultaneously moving the object transverselyrelative to the follower, periodical-ly exposing the light sensitivesurface to a source of light transmitted through a slotted shield whilefthe light sensitive surface is moving to imprint a :scale upon thelight surface, alternately exposing the light sensitive surface to asecond source of lighrt while the light sensitive surface is stationary,and directing the light from said second source to the surface along apath varied in response to variations in the position of fthe follower,whereby a record of successive profile measurements and the scale bywhich they are to be measured are imprinted simultaneously in 1a singlecontinuous operation.

7. In a prole measuring apparatus having .means controlling thedirection of a ray of light in accordance with the prole of an object,the method of concurrently making a measuring scale for receiving saidprofile-positioned rays of light comprising, progressing sensitized filmacross a light transmitting slit, successively directing separated raysof light through the slit onto the film while the lilm is moving to makespaced elongated indications on the film in registration with saidproiile positioned rays of light, and periodically during such series ofsuccessive illuminations of the film intensifying the separater". raysof light to cause the formation of heavier indications on the ilm.

8. In a system of making and recording profile measurements thecombination of a slide provided with means for holding an article to bemeasured, a motor for ad.- vancing the slide, an energizing circuit forthe motor, a motor switch for connecting the energizing circuit to themotor, a feeler to engage the article, a movable mirror operativelyconnected wtih the feeler, a housing adapted to contain a sensitizedfilm, said housing having an en posure slit, a source of illuminationproviding a ray of light adapted to be directed by the mirror throughthe slit onto the lrn to indicate the feeler position, an energizingcircuit for said source, a source switch for connecting the source toits circuit, a second source of illumination adapted to direct lightthrough said slit, another energizing circuit for the second source,another source switch for connecting said second source to its circuit,a grid having a row of spaced openings interposed between the secondsource and the film to form spaced scale indications thereon, a secondmotor, a mechanism operated thereby to progress the iilm periodically, acam mechanism driven by said motor and operably engaging each of saidswitches in predetermined relation to successively energize the slidemotor to move the article, then to energize the second source to make ascale indication and then to disconnect the slide motor and secondsource from their energizing circuits andl energize the first source toindicate the feeler position, and a limit switch controlled by thearticle advancing motor for preventing its advancement beyond apredetermined article limit.

9. In an apparatus for measuring cross sectional distances of an object,the combination of a pair of arms side by side, independent pivots forsaid arms at one end, feelers projecting toward each other and from thearms adjacent their other ends, an inwardly projecting rack on each arm,abutment screws carried by the respective racks and adapted to engageeach other to limit the approach of the free ends of the arms, a pair c"pinions meshing with the respective racks, a mirror carried by eachpinion for reflecting light from a source toward a receiving andindicating medium, and tension means on each of the arms for urgingtheir respective pinions in a direction to absorb the backlash betwecthe pinions and the corresponding racks.

10. In a measuring apparatus, the combination of a movable slide, meansfor holding thereon an article to be measured, a feeler adapted toengage a face of the article, a mirror movable by the feeler, means forhol 'V ing a sensitized film in position to receive a ray of lightadapted to be directed by the mirror to produce visual indications ofthe feeler position, a lamp, a grid between the lamp and the iilm, meansfor directing light from. the lamp through the grid and in spacedregions on the film to produce spaced marks forming a quantitativemeasuring scale in registration with said feeler indications, a switchmechanism to illuminate the scale lamp, means to advance the iilm whilethe scale lamp is illuminated, a resistance in the circuit to the scalelamp and means for periodically short circuiting the resistance toincrease the illumination of the light to make heavier marks on the lm.

1l. An apparatus for producing a chart indicative of measurement of anobject comprising, a housing adapted to contain a sensitized iilm,mechanism for intermittently progressing the iilm across the slit in thehousing, a stationary grid in front of the housing, means for directinglight through the grid and through the slit to act on the lm when the lmis moving, feeler mechanism to engage the object and be moved thereby, amirror, means for directing ylight towards the mirror, means c0- actingbetween the mirror and feeler mechanism to cause the mirror to be turnedby the feeler mechanism and thereby reect light through the slit ontothe lm at a time when it is stationary, and means for alternatelyinterrupting the light through the grid and the light reflected by themirror.

12. An apparatus for producing a chart indicative of measurement of anobject comprising, means for holding and intermittently progressing asensitized film, a stationary grid, means for directing light throughthe grid onto the lm at a time when the film is moving, feeler mechanismfor engaging the object and adapted to be moved thereby for measurement,a mirror, means for directing light towards the mirror, means coactingbetween the mirror and feeler mechanism to cause the mirror to be turnedby the feeler mechanism and thereby reflect light onto the same regionof the lm, means ,operative during measurement of the article foralternately controlling each of said light directing means so thatillumination through the grid occurs at one time and illuminationreflected by the mirror occurs at another time.

13. The combination of means for holding an object to be measured, apair of pivot arms, inwardly projecting feelers carried by therespective arms to engage opposite faces of the object to be measured, apair of independently pivoted mirrors, intermediate mechanism connectingeach mirror respectively for movement with one of the arms, and a pairof mutually overlapping magnets have adjacent opposite poles and eachcarried respectively by one of the arms for mutual magnetic coaction,thereby urging the feelers to approach each other.

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